This invention relates generally to radio frequency (RF) interface resources that provide access to media.
The phrase “RF interface resource” refers to the hardware and software components of transmitters, receivers, and transceivers used by applications to send or receive signals communicated over the radio frequency range of the electromagnetic spectrum, or to process data carried in those signals, or communicated through other means such as over a traditional data network or through a software interface. This data can be in the form of audio, video, voice, data, or any combination thereof. Examples of applications that use media carried over RF signals include TV viewing, music radio listening, and voice/data communication and exchange. RF signals may be carried over a variety of communications links including over-the-air terrestrial sources, satellite sources, and wireless communications networks. In addition to being carried over RF frequencies, data processed by RF interface resources may be communicated in the form of packet-based data carried over traditional copper wire or optical fiber based data communications networks. For example, the data processed by an RF interface resource may be communicated as signals over a television antenna, a DSL modem, a cable modem, a coaxial cable TV connection. Alternatively, data processed by an RF interface resource, such as an MPEG-2 transport stream processed by a demultiplexer, may be carried as data communicated over a USB connection, by a network interface card (NIC) or even through a software programming interface.
A personal computer (PC) may have a television (TV) add-in card installed, which provides TV program viewing on the PC. In addition to viewing of TV as it is broadcast, many of today's newer cards provide video cassette recorder-like functions such as recording TV programs when aired for later viewing, using the hard disk for storage of the program. Some TV cards provide support for both analog and digital television viewing. Particularly with the advent of digital television, TV signals can also carry data services, in addition to normal TV programs. Some examples of data service applications include the delivery and download of movies, music, software, games, news, and Internet content. The applications receiving this content can be customizable according to user preferences to only receive the content the user is interested in. Just like TV programs, these data services may be scattered across many different RF frequencies or “TV channels.”
Conflicts arise between multiple applications wanting to tune to different TV channels at the same time. A TV program recording application may want to tune to channel 3 to record a preselected program, at the same time the user is watching TV with the TV viewer application on channel 5. At the same time, a PC games download service application might need to turn to channel 10 to get the game the user asked for. The first conflict in this example is over which application gets to tune the tuner to its channel. Even if the system had three independent tuners, each with its own demodulator and demultiplexer, a second conflict could occur over the use of a common decoder needed to convert protected or encrypted content into a form useable by each application.
Because current systems allow each application to get direct access to these resources, one application can interfere with the correct operation of other applications, leaving the user clueless as to why a problem occurred. For instance, the TV viewer application, because it lets the user change the TV channel whenever she wants to, may make it impossible for the TV recording application to record desired programs, and the PC games service to successfully download a game (even though the user has paid money for the service). Because of conflicts over the use of these shared resources, the user is usually left completely in the dark as to why the other applications fail (especially if they were the reason why the user invested in a TV card to begin with). The result is equally unsatisfying for data service providers and operators who depend on content being successfully downloaded in order to collect revenue.
Thus, there is a need for ways to resolve contention when the number of active applications requiring the use of an RF interface resource exceeds the number of available RF interface resources.